Atmel AT89C5132 - Manual (Page 7)

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4173ES–USB–09/07
AT89C5132
Table 7. UART Signal Description
Table 8. SPI Controller Signal Description
Table 9. TWI Controller Signal Description
Table 10. A/D Converter Signal Description
Signal
Name Type Description
Alternate
Function
RXD I/O
Receive Serial Data
RXD sends and receives data in serial I/O mode 0 and receives data in serial
I/O modes 1, 2 and 3. P3.0
TXD O
Transmit Serial Data
TXD outputs the shift clock in serial I/O mode 0 and transmits data in serial I/O
modes 1, 2 and 3. P3.1
Signal
Name Type Description
Alternate
Function
MISO I/O
SPI Master Input Slave Output Data Line
When in master mode, MISO receives data from the slave peripheral. When in
slave mode, MISO outputs data to the master controller. P4.0
MOSI I/O
SPI Master Output Slave Input Data Line
When in master mode, MOSI outputs data to the slave peripheral. When in
slave mode, MOSI receives data from the master controller. P4.1
SCK I/O
SPI Clock Line
When in master mode, SCK outputs clock to the slave peripheral. When in
slave mode, SCK receives clock from the master controller. P4.2
SS I
SPI Slave Select Line
When in controlled slave mode, SS enables the slave mode.
P4.3
Signal
Name Type Description
Alternate
Function
SCL I/O
TWI Serial Clock
When TWI controller is in master mode, SCL outputs the serial clock to the
slave peripherals. When TWI controller is in slave mode, SCL receives clock
from the master controller.
P1.6
SDA I/O
TWI Serial Data
SDA is the bidirectional Two Wire data line.
P1.7
Signal
Name Type Description
Alternate
Function
AIN1:0 I A/D Converter Analog Inputs -
AREFP I Analog Positive Voltage Reference Input -
AREFN I
Analog Negative Voltage Reference Input
This pin is internally connected to AVSS.
-